Human beings normally function over a fairly narrow ambient temperature range. Adjustment of the amount and type of clothing may afford some relief from rising or falling ambient air temperature. However, as ambient air temperature steadily rises, conditioning the same by some form of heat extraction is a preferred solution to maintaining comfortable body temperature. Typically, such heat extraction is performed by air conditioners.
Air conditioners operate on the principle of heat absorption, whereby a refrigerant substance may gradually change phase from solid to liquid or from liquid to gas. Unfortunately, most of the known air conditioners are fairly bulky and costly to maintain. Various types of portable or semi-portable air cooling devices have been developed over the years. Most such air cooling devices are designed to cool an enclosed space, for example, rooms of a building, the interior of a motor vehicle, and the like. These air cooling devices must, therefore, be capable of efficiently cooling a relatively large volume of air. Unfortunately, known devices of this type require relatively costly and/or bulky power sources.
Some known air cooling devices utilize indirect conduction of heat between water and air with the cooling effect of air being relatively low. This increases the size and weight of the air cooling device and requires a bigger space for storage and/or installation. Other air cooling devices use a multi-tube type heat exchanger which requires a large quantity of cooling water to flow in a single pass or in a constantly circulating manner. Additionally, the maintenance of the heat exchanger is somewhat troublesome because of the necessity of cleaning the complicated cooling water tubes. Portable air conditioners or swamp cooler systems are designed for spot cooling, not for area cooling, and are, thus, relatively ineffective.